Data display indicators



3,187,326' DATA DISPLAY INDICATGRS Oswald S. Neck and Eric .F.Harris, London, England, assignors to Westinghouse Brake and Signal Company Y Limited, London, England Filed Sept.,30, 1960, Ser. No. 66,255 Claims priority, application Great Britain, Oct. 13, 1959,

2 Claims. (Cl. 340-378) The present invention relates to electro-mechanical display units by :means of which :any one of a number of {differ-ent characters, such as numerals, may be displayed selectively under electrical control. More particularly, the invention is concerned with a unit of this kind having `a display screen, a rotary stencil plate bearing the characters Within `equispaced character spaces, land a single light `beam source to proj-ect on tothe screen the image of whichever of the characters is in the space positioned in alignment with the light beam..

`In 'order to set the stencil plate to the various display positions the invention provides Ia driving `arrangement comprising a permanent magnet rotor and 'la multi-pole stator having la number of energizing windings equal toV 'half the number of characters such that the required number of different position-s of the rot-'or is obtainable by energization of the windings individually with current of the one polarity or the other.V

Display `units in accordance with the invention are suited to the requirements of control panels Where it is becoming common for a large number cf controls and indications to be centralized lon 'a single panel. Thus, if the task [of supervision is to be manageable, the various control and indication element-s inust4 occupy las little space as possible. Whereas `display units 4in use hitherto have included a cluster of separate lamp bulbs, one Kfor each character, the present unit needs only lone land the bulk of the-driving arrangement canV be accommodated within closer boundaries :than the previous bul-b :cluster on account of the number of windings being only half the number of characters. It is these bound-aries of width and height that yare important because when once the size of the display .has been decided neither Iof these dimensions should be much greater in order that, on the one hand, the continuity of a multi-character display :afforded by several units arranged side by :side shall not be :broken by large gaps between consecutive characters, and, :on the other hand, the unit can be inserted in the yfree space between lines of Iother elements.'

The unit is preferably-of aruniform generally rectangular cross section and accommodated therein in the order given' proceeding lengthwise from thel display end are: Ithe screen, a subassenrbly comprising .a lflat circular stencil plate rotatable [about Vthe lengthwise laxis and a iixed lens system, a single llamp 'bulb and mounting therefor, and, lnally, the driving arrangement, the rotor of the latter being `drivingly connected [with the stencil plate fhy a spindle.

The rotor of the driving arrangement may be'caged within formers around which the windings lare wound in planes passing through the axis of rotation or' the rotor. Alternatively, the stator may have the windings lou cores extending parallel to the axis of rotation :and pre-sent pole faces facing one side of the rotor. It, in this latter case, the stator cores are arranged symmetrically in diametrically opposed pairs, the center-s lot the poles of the permanent magnet rotor are displaced langularly by an odd Imultiple of half the :pitch lof the stator cores.

'Ilhe invention will be rfurther described with reference to one particular embodiment adapted 'for use :as a train description indicator and which will be described, lby way ib Patented June 1, 1965 ice of example, with reference to the accompanying drawings, in which: v

FIG. 1 is a plan `View partially in section showing one lform of a `display unit in accord-ance with our invention.

.FIG. 2 is a cross-sectional view taken along line I-'I of FdG. 1, to show to better advantage, the configuration of the magnetic rotor incorporated in the display unit embodying our invention.

FIG. 3 is a View also talken along line I-I of FIG. 1 ibut showing the display unit of Your invention mounted in juxtaposed relation with a similar unit to allow the display of a multi-digit number. Y

'Plil` 4 is 1a cross-sectional View taken along line I-I-II `of IFIG. 1 to better illustrate 'one particular arrangement of a group lof cores spaced in angular relation Vin the display unit embodying our invention.

FIG. 5 isa cross-sectional View ca-leen along line III-III of FIG. 1 to show the information bearing stencil plate.

Similar .reference characters refer to similar parts in cach of the several views.

Referring now to FIG. 1 of the drawings, the front end of a rectangular section casing 19 is closed by a flat transparent screen i12 with a difiiusion layer on its internal surta/ce so that light images projected Ithereon may be visible over a wide langl-e of view. Spa-ced back from the screen there is accommodated a sub-assembly comprising two lpartitions 14 'and `1'6 with a rotary stencil plate 18 interposed in the lspa-ce between them. These partitions lare perpendicular to the lengthwise axis of the casing and the one nearest the screen 12 provides Va bearing 2t) for the front end of a spindle 22 on which the stencil plate 18 is rfixed, this spindle passing through a hole in the other partition 16.

In the present invention, as shown in FIG. 5, the stencil plate 13 has numeral characters ,19 thereon and Inlay have, in addition, other supplementary characters such, for example, as-an asterisk 2.1.

The Vstencil plate 18 is in therform of aV thin ilat disc originally of transparent material which is silk-screen printed so as to leave in a peripheral band the shapes of the numeral characters 19 and other necessary characters pervious to incident light, there being in this band twelve equispaced character spaces of which one, is unoccupied in the case of the characters being an asterisk 21 and ten numeral characters 19. The unoccupied space is generally designatedas 23. Y i

Spaced behind the partitions 14 and 16 is a further partition 24 providing the mounting for a lamp bulb 26. This bulb is eccentrically Vdisposed in relation to the spindle and is aligned with apertures 16a and 14a in the pair of partitions preceding it. In the nearer aperture 16a is a condenser lens 28 by which the light of the lamp bulb is beamed through the character bearing band of the stencil plate `18. In the further aperture 14a -is .a projector lens 30 to project the resulting light image of theV appropriate numeral character 19 or supplementary character on to the screen, at the same time correcting for the eccentricity ot' the beam in relation to the screen.

Behind the lamp bulb mounting partition follows the driving arrangement which comprises a permanent magnet rotor 32 xed to spindle 22, which spindle extends through a hole 24a in the lamp bulb partition 24 and is supported at its rear end in a bearing 36 provided by a fixed stator assembly generally designated 38. This assembly 38 has a ring of six cores indicated 4t) (FIG. 4) equally spaced in angular relation and disposed about a central core 44 of magnetic material whose function will be described below. Cores 40 are arranged symmetrically in diametrically opposed pairs parallel to the axis of the spindle 22 and present pole faces facing, with an interposed air gap, towards the rearward side or, as shown in FIG. 1, on the right-hand side of the permanent magnet rotor. On each of the cores is woun-d a stator winding 46 (FIG. 1) by which each stator core can be separately energized. At the rear end of the unit are suitable terminal pins 48 for plugging into a socket, these pins providing for illumination of the lamp bulb and energization of the separate windings.

As can be seen from FIG. 2, the permanent magnet rotor 32 is slightly cranked or off-set in that the two arms, on an arc covering the shortest distance between them, have the respective pole centers displaced angularly by 180 less half of the pitch of the stator cores, that is to say, by 1509. It should be noted that with this arrangement one or the other of the rotor tips is never over 150 from the farthest `stator cores. From any one position to another, therefore, the `forces on the rotor are always unbalanced and any movement of the rotor of less than 180 takes place via the shortest route. The tips 32a and 32b of the rotor are extended and bent at rightangles so that when the rotor moves toward an energized stator core, the reluctance gradually decreases. When the energized core is actu-ally reached the reluctance suddenly decreases, giving a substantial holding force and precise positioning.

It will be evident that two different positions of the rotor are obtained by energizing any one of the stator windings with current of one polarity or current of the opposite polarity. The return path between the ends of the cores for the magnetic ux is via the rotor 32 and center core 44. Thus, for all possible modes of energizing the six windings individually, twelve positions of the rotor are obtainable. Each such position corresponds by virtue of the spindle connecting the rotor to the stencil plate 18 to the alignment of a different character space with the light beam. Any one of the available characters may therefore be displayed by energizing the appropriate winding with the appropriate polarity. The lamp bulb may burn steadily, or if necessary it may be extinguished momentarily on changing 1of the display in order .that any oscillations of the stencil plate 18 in settling in its fresh position after a large swing may not be apparent on the screen.

Moreover, it will be appreciated that by providing a larger number of stator windings and associated cores, and by modifying the shape of the permanent magnet rotor in accordance with the change in pitch brought about by the increased number of cores, an arrangement allowing for the display of a greater number of characters may be obtained.

From its front -to rear ends the casing is of the same rectangular section, slightly higher than wide, and therefore a bank of units may be assembled side by side in a panel for the purpose of displaying multi-digit numbers, as we have shown in FIG. 3. In this case, a masking arrangement at the screen may be provided `to prevent adjacent digits from being displayed.

Although we have herein shown and described only one form of data display indicator embodying our invention, it will be understood that various changes and modications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. A data display indicator including a case provided at one end with a viewing screen, a rotary disc having character information thereon located within said case, means for projecting the image of at least one of the characters on said disc onto said screen, shaft means concentric with said disc for supporting it, a permanent magnet rotor rigidly mounted on said shaft to effect synchronous movement of the rotor and said disc, a plurality of core members arranged circumferentially about and parallel to the axis of said shaft means and presenting pole faces facing the side of said rotor opposite that facing said disc, said pole faces being angularly displaced from an adjacent pole face by the same pitch, a winding on each of said core members for selectively polarizing said core members individually, the centers of the rotor poles being displaced angularly by a multiple of half the pitch of said pole faces, means enclosed by said core members between their ends for completing a magnetic flux path between the ends of a core member when said core member is polarized, said permanent magnet rotor having two distinct positions for each polarity of each one of said core members, said permanent magnet rotor moving into attracted magnetic relation with lsaid core member `in accordance with the polarization of said core members to cause the projection onto said screen of a character determined by the position of said rotor.

2. A data display indicator comprising a rotary stencil plate bearing a plurality of characters within equispaced character spaces, a light source to project the image of l whichever of the characters is in the space positioned in alignment with the light source, a spindle on which said stencil plate is fixed, a permanent magnet rotor mounted on said spindle concentric with said stencil plate, a plurality of core members presenting pole faces facing the side of said rotor 4opposite that facing said stencil plate, said pole members circumferentially arranged parallel to and symmetrically around the axis of said spindle, a central core enclosed by said core members and extend ing substantially between the ends of said core members along said axis, a winding on each of said core members for selectively polarizing said core members individually, whereby the oppositely poled arm of said rotor is attracted into magnetic relation with the polarized core member, the tips of said rotor being bent toward the pole faces of said core members so that when said rotor moves toward the polarized core member the reluctance gradually decreases and then suddenly decreases when said polarized core member is actually reached.

References Cited bythe Examiner UNITED STATES PATENTS 594,979 12/ 97 Barrett. 1,464,103 8/ 23 Nash. 1,492,913 5/24 Wood. 2,155,929 4/ 39 Breitenstein.

2,253,980 8/41 Parker 340-378 2,287,241 6/42 Hallerberg 340-378 FOREIGN PATENTS 1,038,523 6/51 France.

382,228 10/ 32 Great Britain.

NEIL C. READ, Primary Examiner.

MILTON M. FIELD, Examiner. 

1. A DATA DISPLAY INDICATOR INCLUDING A CASE PROVIDED AT ONE END WITH A VIEWING SCREEN, A ROTARY DISC HAVING CHARACTER INFORMATION THEREON LOCATED WITHIN SAID CASE, MEANS FOR PROJECTING THE IMAGE OF AT LEAST ONE OF THE CHARACTERS ON SAID DISC ONTO SAID SCREEN, SHAFT MEANS CONCENTRIC WITH SAID DISC FOR SUPPORTING IT, A PERMANENT MAGNET ROTOR RIGIDLY MOUNTED ON SAID SHAFT TO EFFECT SYNCHRONOUS MOVEMENT OF THE ROTOR AND SAID DISC, A PLURALITY OF CORE MEMBERS ARRANGED CIRCUMFERENTIALLY ABOUT AND PARALLEL TO THE AXIS OF SAID SHAFT MEANS AND PRESENTING POLE FACES FACING THE SIDE OF SAID ROTOR OPPOSITE THAT FACING SAID DISC, SAID POLE FACES BEING ANGULARLY DISPLACED FROM AN ADJACENT POLE FACE BY THE SAME PITCH, A WINDING ON EACH OF SAID CORE MEMBERS FOR SELECTIVELY POLARIZING SAID CORE MEMBERS INDIVIDUALLY, THE CENTERS OF THE ROTOR POLES BEING DISPLACED ANGULARLY BY A MULTIPLE OF HALF THE PITCH OF SAID POLE FACES, MEANS ENCLOSED BY SAID CORE MEMBERS BETWEEN THEIR ENDS FOR COMPLETING A MAGNETIC FLUX PATH BETWEEN THE ENDS OF A CORE MEMBER WHEN SAID CORE MEMBERS BETWEEN POLARIZED, SAID PERMANENT MAGNET ROTOR HAVING TWO DISTINCT POSITIONS FOR EACH POLARITY OF EACH ONE OF SAID CORE MEMBERS, SAID PERMANENT MAGNET ROTOR MOVING INTO ATTRACTED MAGNETIC RELATION WITH SAID CORE MEMBER IN ACCORDANCE WITH THE POLARIZATION OF SAID CORE MEMBERS TO CAUSE THE PROJECTION ONTO SAID SCREEN OF A CHARACTER DETERMINED BY THE POSITION OF SAID ROTOR. 